Phase variable device for engine

Abstract

OBJECT: To provide a compact phase varying device for an automobile engine, adapted to vary the relative phase angle between the crankshaft of the engine and the camshaft of the device over a wider range than that of conventional device. MEANS FOR ACHIEVING THE OBJECT: The phase varying device has: a drive rotor driven by the crankshaft of the engine; a first control rotor rotatable relative to the drive rotor under the action of a torque means; and a phase angle varying mechanism operably coupled to the first control rotor in rotational motion relative to the first control rotor, the drive rotor and first control rotor rotatably supported by a camshaft of the phase varying apparatus, the phase varying device adapted to vary the phase angle of the camshaft relative to the crankshaft by varying the phase angle of the camshaft relative to the drive rotor. The phase angle varying mechanism is characterized by comprising: a first circular eccentric cam integrated with the first control rotor and having a center eccentrically offset from the rotational axis of the camshaft; a second circular eccentric cam integrated with the camshaft and having a center eccentrically offset from the rotational axis of the camshaft; a cam guide member for rotatably coupling the first circular eccentric cams with the second circular eccentric cam and for converting the eccentric rotational motion of the first circular eccentric cam into the eccentric rotational motion of the second circular eccentric cam.

The invention claimed is: 
     
       1. A phase varying device for use with an automobile engine, comprising:
 a drive rotor driven by the crankshaft of the engine; 
 a first control rotor rotatable relative to the drive rotor under the action of a torque means; and 
 a phase angle varying mechanism operably coupled to the first control rotor in rotational motion relative to the first control rotor, the drive rotor and first control rotor rotatably supported by a camshaft of the phase varying apparatus, the phase varying device adapted to vary the phase angle of the camshaft relative to the crankshaft by varying the phase angle of the camshaft relative to the drive rotor, 
 wherein the phase angle varying mechanism includes:
 a first circular eccentric cam integrated with the first control rotor and having a center eccentrically offset from the rotational axis of the camshaft; 
 a second circular eccentric cam integrated with the camshaft and having a center eccentrically offset from the rotational axis of the camshaft; 
 a cam guide member for rotatably coupling the first circular eccentric cams with the second circular eccentric cam and for converting the eccentric rotational motion of the first circular eccentric cam into the eccentric rotational motion of the second circular eccentric cam, thereby varying the phase angle of the camshaft relative to the drive rotor in accord with the eccentric rotational motion of the second circular eccentric cam relative to the first circular eccentric cam. 
 
 
     
     
       2. The phase varying device according to  claim 1 ,
 wherein the drive rotor includes radial guide grooves that extend in substantially radial directions perpendicular to the rotational axis of the camshaft; and 
 wherein the cam guide member includes
 a pair of grip sections penetrating the radial guide grooves to grip the outer circumference of the first circular eccentric cam by the opposite sides, the grip sections movable in the radial guide grooves in response to the eccentric rotational motion of the first circular eccentric cam; and 
 an oblong circular hole extending in the direction perpendicular to the radial guide grooves and slidably accommodating therein the second circular eccentric cam so as to displace the second circular eccentric cam in the direction perpendicular to the radial guide grooves. 
 
 
     
     
       3. The phase varying device according to  claim 1  or  claim 2 , wherein the torque means comprises:
 a first control means for rotating the first control rotor in the phase retarding direction relative to the drive rotor; and 
 a reverse mechanism for rotating the first control rotor in the phase advancing direction relative to the drive rotor. 
 
     
     
       4. The phase varying device according to  claim 3 ,
 wherein the reverse mechanism comprises:
 a second control rotor rotatable relative to the camshaft; 
 a second brake means for putting a brake on the second control rotor so as to rotate the second control rotor in the phase retarding direction relative to the first control rotor; and 
 a ring mechanism for rotating the first control rotor in the phase advancing direction relative to the drive rotor when the second braking means is in operation, and wherein the ring mechanism includes: 
 a first ring member in sliding contact with a first circular eccentric hole formed in the first control rotor; 
 a second ring member in sliding contact with a second circular eccentric hole formed in the second control rotor; 
 an intermediate rotor having a radial guide groove and being rotatable together with the camshaft; and 
 an eccentric coupling member passing through the radial guide groove of the intermediate rotor and movable in the radial guide groove, the eccentric coupling member having opposite ends rotatably coupled to the first and second ring members, respectively, to allow for relative eccentric rotations of the first and second ring members.